“I thought about calling it a career,” Duncan said Tuesday in an interview with David Letterman, per mysanAntonio.com. “But I felt I could at least do one more year. I felt I was still effective. I felt I could still play and help the team.”

Duncan, 38, was highly effective in the Spurs' run to a fifth NBA championship, averaging 16.3 points and 9.1 rebounds in the playoffs. With San Antonio's other key players returning as well, Duncan's chances of earning a sixth ring are good. All the more reason for him to opt in — that, and the $10.3 million salary.